Latching device

ABSTRACT

A positive acting latching device particularly suited for dental units comprises guide rods that have a forward and rearward end. A carriage is carried on the guide rods and is slidable relative thereto. An elongated rail is positioned parallel to the guide rods and has a lateral leading edge spaced from the forward end of the guide rods. A control member is placed between the guide rod&#39;&#39;s forward end and the rail leading edge. A toggle formed with two opposed notches is attached to the carriage and is pivotable thereon. The toggle is operable to slide adjacent the rail and strike the control member whereby it orients the notch so that when the toggle moves back and strikes the leading edge, the leading edge coacts with the notch and locks the toggle and carriage thereat. Release is accomplished by moving the toggle from the leading edge causing it to strike the control member. In so doing, the control member orients the toggle and allows it to move past the rail leading edge towards the rearward end of guide rods.

[ Sept. 23, 1975 United States Patent Buono LATCHING DEVICE for dentalunits Comprises guide rods that have a for- Inventor: Joseph Buono 86 75Midland Pky ward and rearward end. A carriage is carried on the Apt. 3T,Jamaica, NY. 11432 Oct. 21, 1974 guide rods and is slidable relativethereto. An elongated rail is positioned parallel to the guide rods andhas a lateral leading edge spaced from the forward end of the guiderods. A control. member is placed between the guide rod dge. A toggleform [22] Filed:

s forward end and the rail leading 21 App]. No.2 516,392

e ed with two opposed notches is at- [52] US. 74/527; 74/520 tached tothe carriage and is pivotable thereon. The

Int. Cl. GOSG 5/06 toggle is operable to slide adjacent the rail andstrike the control member whereby it orients the notch so that when thetoggle moves back and strikes the leading edge, the leading edge coactswith the notch and locks the toggle and carriage thereat. Release is ac-References Cited UNITED STATES PATENTS complished by moving the togglefrom the leading edge causing it to strike the control member. In so do-3,436 983 4/1969 74 521 the control member miems the toggle and allowsit to move past the rail leading edge towards the rearward end of guiderods.

Primary Examiner-Samuel Scott or FirmLeonard H. King ABSTRACT A positiveacting latching device particularly suited 6 Claims, 4 Drawing FiguresUS Patent Sept. 23,1975 Sheet 1 of2 3,906,815

US Patent Sept. 23,1975 Sheet 2 of2 LATCHING DEVICE FIELD OF THEINVENTION This invention relates to a retraction mechanism for a hose orcable, or the like, and more particularly to a retraction device havingmeans to latch the hose in an extended position.

BACKGROUND OF THE INVENTION Many instruments particularly those used bydentists are attached to cables or hoses through which the variousfluids, gases or motive means are supplied. For example, the familiardentists rack contains an array of instruments some of which utilizefluid pressure, vac'- uum, electric or ultrasonic power. Since the rackis p sitioned remote from the patient, it is obvious that an appreciableamount of cable or hose need be stored in the rack so that theinstrument can reach the patient. Some means then is necessary to rewindor retract the cable back into the rack. Usually the rewind sequence isaccomplished by biasing the hose or cable with linear acting springsthat provide a constant tension against which the dentist must pull ashe withdraws the instrument from the rack. Unless some type of lockingor stop action is provided an unacceptable pulling or retractive forceis experienced by the dentist as he uses the instrument. While theamount of tension exhibited by those linear acting springs is minimal,the tension in the line would unduly confine or interfere with use ofthe instrument. Some type of locking action is needed to lock a portionof the cable and thereby free the extended end of the hose which carriesthe instrument. The reliability of these locking devices is critical.If, for example, a dentist is drilling a tooth, the positioning of thedrill is of utmost importance. With the power line being extended fromthe instrument during this opera tion, and the line locked while soextended, the biasing or retracting force on the line is counteracted,hence, the dentist uses the instrument freely. If the locking devicewere to fail the cord or hose will rapidly retract jerking theinstrument with potentially disasterous results.

To avoid such failures prior apparatus have gone'to extensive andcomplicated lengths to insure the reliability of the cable lock orlatching means. Prior devices have used ratchet blocks, locking pins orvarious frictional devices to lock the cable. For example, US. Pat. No.3,436,983 discloses a latch structure for pull lines. In part, thedevice utilizes the elasticity inherent in a hook element whose bendingand flexing permits it to engage a V-shaped member that is tilted withrespect to the path of travel. Upon release, the hook element must thenalign properly so that it can pass through an accurately placed opening.

Generally, the present invention employs a pivotal toggle extending froma carriage. The dental cable or hose passes over a pulley attached tothe carriage. The toggle has opposed longitudinal edges and at itslateral edges is formed with a pair of opposed notches that inconjunction with the longitudinal edges provide a plurality of surfaces.The position of these surfaces in relation to and acting on a controlmember, which is a stop, effect a locking or latching action. Thecarriage assembly slides adjacent to a rail with the rail defined by aleading edge. As the cable is withdrawn from the apparatus the togglestrikes the control member stopping forward movement of the carriage andattached cable.

In so doing the control member acts to orient the toggle so that whenthecable is momentarily released, the cable and carriage undergo aretractive movement until the toggle strikes and locks about the railleading edge. To release the cable, the cable is pulled a short distancefrom the rack causing the toggle to engage the control stop. This actionorients the toggle so that same is then able to slide past the railleading edge as the cable retracts. Since no flexing of the lockingelements is required, fatigue inherent from such bending is eliminated.

It is therefore an object of the present invention to provide a lockingdevice particularly suited for use in locking retractable cables, hosesand the like.

It is another object of the present invention to provide a positivelyacting latching mechanism having a one stop lock position whose releasetherefrom depends on a forward pull on the cable.

It is still a further object of the present invention to provide alocking apparatus particularly suited for retractable cables that issimple in design, easy to manufacture, and one that will providereliable locking and releasing action. I

Other objects and features of the present invention will become apparentfrom the following detailed description considered in connection withthe accompanying drawings. It is to be understood however that thedrawings are designed for purposes of illustration only and not as adefinition of the limits of the invention for which reference should bemade to the appending claims.

BRIEF DESCRIPTION OF DRAWINGS In the drawings wherein similar referencenumerals denote similar elements throughout the several views:

FIG. 1 is a perspective view of the locking device positioned in adental unit with a part of the unit broken away for clarity;

FIG. 2 is an elevational view of the inventive carriage assembly andattached toggle that is revealed in FIG. 1;

FIG. 3 is an enlarged partial perspective view of the apparatus of FIGS.1 and 2 showing suspension of the notched toggle from the carriage andpulley support and positioned between the guide rail and control stop;and

FIG. 4 shows the sequence of positions through which the inventiveapparatus traverses to provide the unique one-stop latching feature.

DETAILED DESCRIPTIONS OF THE PREFERRED EMBODIMENT Referring now to thedrawings and particularly FIGS. 1, 2, and 3, there is shown theapparatus of the present invention operable in a dental unit. A dentalunit indicated generally by reference numeral 10 comprises a cowling 12,a front panel 14 and a rear panel 15. Panel 14 includes a plurality ofapertures 16 through which the various dental instruments are arranged.A plurality of guide rods 18 are disposed :in unit 10 and attachedbetween the front and rear panel so that a pair of guide rods is spacedparallel adjacent each aperture as shown. A carriage 20 is formed with apair of opposed channels 22. The channels are dimensioned so as to fitabout the periphery of respective rods 18. With the construction shown,carriage 20 is able to slide along rods 18 while being confined thereon.A support strut 24 is attached toone face of carriage 20 by means 28while a pulley 26 is attached to the other face of carriage 20 by thesame means. Support 24 is formed with a right-angled extension 30 thatprojects outboard from the face of carriage 20, as more clearly seen inFIG. 2. A toggle or pawl piece 32 is pivotably suspended from one sideof arm 30 by a pin 34. Hence toggle 32 is operable to rotate relative toarm 30.

Toggle 32 is defined by a pair of parallel opposed longitudinal edges 36and 38 which define the two longitudinal sides of the toggle. Theopposed lateral sides of the toggle are defined by complimentary,although oppositely positioned notches 40 and 42. Notch 40 is defined bya relatively long side or face 44 and a short side or face 46 with thefaces merging at a common edge or point. In a similar manner, notch 42is defined by a relatively long side or face 48 and a relatively shortface 50 that likewise merges along a common edge or point. It will beobserved, however, that positions of the respective long and short facesof each notch are reversed. That is, whereas notch 42 has long face 48merging with a longitudinal edge 36, notch 40 has its short face mergingwith this last mentioned edge. Hence when comparing one notch to theother it will be observed that the respective faces thereof arereversed.

Positioned in housing is a control block or stop 52. Control block 52 isattached to the floor of the housing and is placed adjacent to frontpanel 14. The height of control block 52 as well as the lateral distancefrom a plane defined by connecting a respective rod pair 18, is such asto insure that the toggle will strike block 52 so that the block acts asa stop for the toggle. Control block 52 includes a control edge 53 whoseoperation will be described hereinafter.

Positioned rearward of control block 52 and disposed substantiallyparallel to the plane defined by rods 18 is a guide rail 54. Guide rail54 includes a leading edge 56 disposed so as to face control block 52.

A cable or hose 58 is carried on pulley 26 so that free end of the hoseextends through aperture 16 where it may be coupled onto a given dentalinstrument 62. Thus, the hose or cable, as the case may be, carries, forexample, fluid pressure, electric current, or the various dentalutilities. The other end of hose 50 extends through a rearward portionof unit 10 where it may be coupled to the given dental utility, thedental utility, now shown.

A constant tension spring, 60, one such spring being known in the art asa Neg-A-Tor, is on one end attached to rear panel of unit 10, and on theother end the spring is coupled to carriage 20. Spring 60 normallybiases carriage towards a retracted position causing the carriage toslide on rods 18 until nearly adjacent the rear panel.

Operation of the inventive device can best be understood by reference toFIG. 4 and referring back to FIGS. 1, 2 and 3. As noted, constanttension spring 60 normally biases carriage 20 into a retracted positionwith carriage 20 nearly adjacent rearward wall 15 and unit 10. In thisretracted position, instrument 62 extends into aperture 16 by beingpulled therethrough by cable 58 as the cable and carriage is urgedrearward in unit 10 by action of the spring.

To withdraw the instrument the following sequence of movements occur andnow particular reference is made to FIG. 4. As the dentist pulls oninstrument 62, carriage 20 begins to slide on rods 18, causing toggle 32to move relative to rail 54. In this configuration, longitudinal edge 38of the toggle is spaced opposed from the inboard face of rail 54. In theposition shown at 32a, toggle 32 is about to leave the region of rail 54and is moving in the direction of arrow 1. Continued pull on cable 58causes toggle 32 to strike stop 52 stopping forward movement of thecarriage. More particularly, the dimensional constrants of the inboardface of rail 54 in relation to longitudinal edge 32 mandates that as thetoggle leaves the region of rail 54 in the direction indicated, toggle32 is positioned with notch 40 facing con trol stop 52. In thisconfiguration, face 46 is in a position to strike control edge 53. Asthe toggle strikes control block 52, the position at 32b is obtained.Further application of tension in the direction of arrow 1 causes apivoting of toggle 32 as carriage 20 moves a small distance forward. Thetoggle pivots about control edge 53 until reaching the position shown inat 32c where toggle face 44 abuts against control 52 stopping anyfurther forward movement of carriage 20. At this point the carriage, andso cable, is in its most extended position. A momentary release of theinstrument or the cable, depending which is held, allows spring 60 topull the carriage back towards rear panel 15. In so doing, the carriagemoves toggle 32 in the direction of the arrow 2 causing the relativelylong face 44 of notch 40 to slide along control edge 53. The sliding onedge 53 acts to orient the toggle to the position shown at 32d. Spring60 continues to urge carriage 20 and hence toggle 32 in the direction ofarrow 2 until edge or face 50 of notch 42 strikes leading edge 56 ofrail 54. At this point the configuration indicated at 32e is assumed.Spring 60 continually applies tension to the carriage causing a slightmovement of the carriage and pivoting of toggle 32. This pivoting drivesthe leading top of toggle face 48 onto the inboard surface of rail 54.This is indicated at position 32f, where toggle 32 is prevented fromfurther travel towards rear panel 15. The toggle remains so configuredby application of tension from spring 60. In the position of 32f thetoggle jams against the rail and so is latched or locked from movingfurther in direction of arrow 2.

To release the toggle and retract the cable and dental instrument, onemerely tugs on either the instrument or extended cable portion causingtoggle 32 to move in direction of arrow 3 and strike control edge 53 asshown at position 32g. Further pulling on the cable or instrument indirection of arrow 3 causes longitudinal edge 38 of the toggle to sliderelative to and on control edge 53 and in so doing pivots toggle 32 intothe position indicated at 3211. At this configuration the toggle andcarriage are prevented from further movement in the direction of arrow 3so that a momentary releasing of the instrument or cable, as the casemay be, allows spring 60 to urge carriage 20 in the direction of arrow 2which is towards guide rail 54. As toggle 32 travels towards guide rail54 and strikes same, the position shown at 321' is reached where aportion of longitudinal face 36 of the toggle strikes leading edge 56 ofrail 54 thereby acting to slightly pivot the toggle and drive it to theposition shown at 32j. In this last mentioned position, spring 60 isthen free to retract carriage 20 as the toggle slides rearward lightlywiping against, or spaced parallel from the inboard face of rail 54.Completion of the above sequence from, 32a to 32j causes the toggle torotate on pin 34. This rotation has now placed notch 42 in a position torepeat the above action.

Of course it is to be understood that the above action is fast acting sothat in effect the operation of the device produces two independentsequences, one for lock and one for release. The first sequence iswithdrawal of the instrument until the pawl hits the control stop, thena momentary release allowing the carriage to travel a minute distanceback towards rear panel until toggle 32 locks or latches against theleading edge of reel 54.

The second sequence is for unlock, where a forward tug on the instrumentcauses the toggle to strike and stop against control block 52reorienting the toggle and allowing it to slide past and adjacent torail 54 retracting the cable when the cable or instrument is released.

It will be appreciated that owing to the inherent sim'- plicity in theinventive apparatus the same will be virtually maintenance free and freefrom periodic adjustment.

While reference has been made to the guide rods being mounted betweenthe front and rear panels, it should be appreciated that the chassis maycarry brack ets for mounting the guide rods without departing from thespirit of the invention.

While the latching apparatus of the present invention has been shown anddescribed in connection with dental apparatus utility therefor is not tobe limited thereby. The inventive lock will find utility in a variety ofmachines where it is necessary to detachably lock one part in relationto another.

While only a single embodiment of the present invention has been shownand described, it is to be understood that many changes andmodifications may be made hereto without departing from the spirit andscope thereof.

What we claim as new and desire to secure by Letters Patent is:

1. A latching device comprising:

a. guide means having forward and rearward ends;

b. a carriage by said guide means and slidable relative thereto;

c. an elongated guide rail parallel to said guide means and having alateral leading edge spaced from said guide means forward end;

d. a control piece placed intermediate said guide means forward end andthe leading edge; and,

e. toggle means formed with notch means and attached to said carriageand pivotal thereon, said toggle means operable to strike said controlpiece and orient said notch means so that when said toggle means strikesthe leading edge, the leading edge will coact with said notch means tolock said toggle means and carriage thereat, then when said toggle meansis caused to strike said control piece, said control piece will orientsaid toggle means allowing it to move past the leading edge and permitsaid carriage to traverse said guide means toward said rearward end.

2. The device of claim 1 further comprising biasing means adapted tonormally urge said carriage towards said rearward end.

3. The device of claim 2 further including:

a. pulley means attached to said carriage;

b. line means having two ends and wrapped about said pulley means sothat pulling one of said two ends causes the relative movement of saidcarriage whereby said one line end moves to an extended position as saidtoggle means assumes said locked configuration, said one line end beingautomatically driven into a retracted position by operation of saidbiasing means when said toggle means is so orientated that it passes theleading edge and traverses towards said rearward end.

4. The device of claim 3 enclosed in a console, the console defined by aforward face having a plurality of apertures formed therethrough, andwherein said one line end extends through one of said plurality ofapertures, and the other end of said line extends from said console.

5. A positive acting latch comprises in combination:

a. a dental unit having a front panel and a rear panel opposed theretowith said front panel being formed with at least one aperturetherethrough;

b. a pair of guide members adjacent said aperture and extending betweensaid front and rear panels;

c. a carriage having a pulley and slidable relative to said guidemembers for confinement thereby;

d. an elongated rail substantially parallel to said guide members andhaving a leading edge spaced from said front panel;

e. a stop having a control edge that faces said rail leading edge;

f. pawl means formed with notch means and attached to said carriage andpivotal thereon;

g. spring means normally biasing said carriage towards the rear panel;and

h. a dental line having two ends one of which enters said unit and wrapsaround the pulley so that the other line end exits through said aperturewhereby pulling on said other line end allows a portion of said line toexit said aperture as said pawl means and carriage slides relative tosaid guide rail and past said leading edge until said notch meansthereof strikes said control edge a first time to limit movement of saidline, then momentarily releasing said line allows said carriage to moveback towards, and strike, said leading edge locking said pawl meansthereabout, then pulling on said line other end causes said pawl meansto strike said control edge a second time orienting said pawl meanswhereby releasing said line permits said spring means to drive said pawlmeans past leading edge returning said carriage and line adjacent saidrear panel.

6. A retractable cable assembly and lock therefore,

comprising:

a. a guide element having a forward and rearward end;

b. a carriage movable relative to and on said element and coupled to thecable;

c. an elongated rail substantially parallel to said element and having aleading edge spaced rearward of said element forward end;

d. a stop block placed intermediate said element forward end and saidleading edge; and

e. pawl means formed with a pair of opposed V- shaped grooves andpivotally attached to said carriage, said pawl means operable to strikesaid stop block and orient the grooves so that when said pawl means iscaused to strike said leading edge, the same will coact with one of saidgroove pair to lock said pawl means and carriage thereat whereby thecable assumes an extended position, then when said toggle means iscaused to strike said block, said block will orient said pawl meansallowing it to move passed said leading edge permitting said carriagc totraverse said element towards said rearward end thereof driving thecable to a retracted position.

1. A latching device comprising: a. guide means having forward andrearward ends; b. a carriage by said guide means and slidable relativethereto; c. an elongated guide rail parallel to said guide means andhaving a lateral leading edge spaced from said guide means forward end;d. a control piece placed intermediate said guide means forward end andthe leading edge; and, e. toggle means formed with notch means andattached to said carriage and pivotal thereon, said toggle meansoperable to strike said control piece and orient said notch means sothat when said toggle means strikes the leading edge, the leading edgewill coact with said notch means to lock said toggle means and carriagethereat, then when said toggle means is caused to strike said controlpiece, said control piece will orient said toggle means allowing it tomove past the leading edge and permit said carriage to traverse saidguide means toward said rearward end.
 2. The device of claim 1 furthercomprising biasing means adapted to normally urge said carriage towardssaid rearward end.
 3. The device of claim 2 further including: a. pulleymeans attached to said carriage; b. line means having two ends andwrapped about said pulley means so that pulling one of said two endscauses the relative movement of said carriage whereby said one line endmoves to an extended position as said toggle means assumes said lockedconfiguration, said one line end being automatically driven into aretracted position by operation of said biasing means when said togglemeans is so orientated that it passes the leading edge and traversestowards said rearward end.
 4. The device of claim 3 enclosed in aconsole, the console defined by a forward face having a plurality ofapertures formed therethrough, and wherein said one line end extendsthrough one of said plurality of apertures, and the other end of saidline extends from said console.
 5. A positive acting latch comprises incombination: a. a dental unit having a front panel and a rear panelopposed thereto with said front panel being formed with at least oneaperture therethrough; b. a pair of guide members adjacent said apertureand extending between said front and rear panels; c. a carriage having apulley and slidable relative to said guide members for confinementthereby; d. an elongated rail substantially parallel to said guidemembers and having a leading edge spaced from said front panel; e. astop having a control edge that faces said rail leading edge; f. pawlmeans formed with notch means and attached to said carriage and pivotalthereon; g. spring means normally biasing said carriage towards the rearpanel; and h. a dental line having two ends one of which enters saidunit and wraps around the pulley so that the other line end exitsthrough said aperture whereby pulling on said other line end allows apOrtion of said line to exit said aperture as said pawl means andcarriage slides relative to said guide rail and past said leading edgeuntil said notch means thereof strikes said control edge a first time tolimit movement of said line, then momentarily releasing said line allowssaid carriage to move back towards, and strike, said leading edgelocking said pawl means thereabout, then pulling on said line other endcauses said pawl means to strike said control edge a second timeorienting said pawl means whereby releasing said line permits saidspring means to drive said pawl means past leading edge returning saidcarriage and line adjacent said rear panel.
 6. A retractable cableassembly and lock therefore, comprising: a. a guide element having aforward and rearward end; b. a carriage movable relative to and on saidelement and coupled to the cable; c. an elongated rail substantiallyparallel to said element and having a leading edge spaced rearward ofsaid element forward end; d. a stop block placed intermediate saidelement forward end and said leading edge; and e. pawl means formed witha pair of opposed V-shaped grooves and pivotally attached to saidcarriage, said pawl means operable to strike said stop block and orientthe grooves so that when said pawl means is caused to strike saidleading edge, the same will coact with one of said groove pair to locksaid pawl means and carriage thereat whereby the cable assumes anextended position, then when said toggle means is caused to strike saidblock, said block will orient said pawl means allowing it to move passedsaid leading edge permitting said carriage to traverse said elementtowards said rearward end thereof driving the cable to a retractedposition.